Acoustical well sounder



July 17, 1951 A. WOLF 2,560,911

v v ACOUSTICAL WELL SOUNDER Filed July 24, 1947 2 Sheets-Sheet l I I I) III | I'll [AI/A III] I III/l4.

ALEXARDER WOLF IN V EN TOR.

ATTORNEY July 17, 1951 A. WOLF 2,560,911

AGOUSTICAL WELL SOUNDER 9 Filed July 24, 1947 2 Sheets-Sheet 2 ALEXANDER WOLF IN V EN TOR.

FIG.2

ATTORNEY Patented July 17, 1951 UNITED STATES PATENT OFFICE ACOUSTICAL WELL SOUNDER Alexander Wolf, Houston, Tex., assignor to Keystone Development Corporation, Houston, Tex., a corporation of Texas Application July 24, 1947, Serial No. 763,217

3 Claims. I

and particularly to acoustical well sounding devices.

In the operation of producing oil wells information is sometimes required as to the depth to the top of the fluid in the annular space between the casing and the tubing. Thus fluid level which is too high may point to a defective pump, which is not removing all the oil which might flow into the well. At other times, from the height of the fluid column, its known density, and the gas pressure in the casing at the surface of the ground one may calculate the pressure at the bottom of the well. This pressure is of great interest to the petroleum engineers concerned with the efficient operation of an oil-field, and with the prediction of the ultimate oil recovery from a given field.

Purely mechanical means have been devised for determining the height of fluid in a well. However, the ordinary producing oil-well contains within its casing another string of smaller pipe, called the tubing, through which the oil actually flows. In the case of a pumping well this tubing may contain a string of rods, called sucker-rods, which move up and down, and thus operate a plunger pump attached to the bottom of the tubing. It is obvious that for mechanical sounding both the sucker-rods and the tubing with the pump must be removed from the well. This involves considerable expense and some delay in operations. Moreover, the removal of the pump may defeat its own purpose, since it may be the intention of the engineer to study the variations in fluid level as the pump is operated in diverse ways, and this obviously cannot be done when the pump is not in the wellv It is thus of great advantage to be able to determine the fluid level in an oil-well by means which do not require the removal of tubing and pump. Such a measurement can be accomplished with a sound wave, propagated in the annular space between the tubing and the casing, and reflected back by the .top of the fluid.- It is true that the velocity of sound in the well-gases varies from well to well, but this does not present any difficulty, since in addition to the sound reflected by the top of the fluid there occur also weaker reflections from the succession of tubing collars. From the known spacing of these collars in the well the sound velocity is readily calculated.

The basic art of determining fluid level by acoustic means is not neW. Various means have been devised for carrying out the measurement, but most of these have certain drawbacks, which the present invention tends to eliminate. Thus one apparatus employs compressed gas, suddenly released, as the source of sound, and a large and delicate membrane, mechanically coupled to a rotatable mirror as the sound receiver. It is obviously inconvenient to carry the large drums of compressed gas which are required, and the delicate receiving means requires great care, and therefore highl skilled engineers for its operation. Another apparatus employs electric blasting caps for the generation of sound; electrical blasting caps are well known to be dangerous and their transportation and storage are closely regulated. Still other devices employ blank cartridges for the generation of sound. similar to the cartridges used in the present invention, but the firing and sound receiving means are unnecessarily bulky and complicated, a very serious disadvantage, because the firing of black powder produces a deposit which must be cleaned out, so that a. frequent disassembling of the device cannot be avoided.

Accordingly, it is a principal object of this invention to provide simple and compact means for generating a sound-wave, transmitting it into the annular space between the tubing and the casing of an oil-well, and subsequently receiving and recording the various sound reflections returned by this space.

Other and more specific objects and advantages,

showing attached thereto a well sounder in ac cordance with said illustrative embodiment;

Fig. 2 is a axial cross-section of the sound generator and receiver; K

Fig. 3 is another cross-section of the sound generator and receiver, taken along line 33 of Fig. 2, and showing the details of the firing mechanism;

Fig. 4 is a view of a cam, which forms a part of the firing mechanism;

Fig. 5 is a plan view of one of the elements of the device; and

Fig. 6 is a cross-sectional detail taken alon line 6--6 of Fig. 5.

Reference is made to Fig. 1 which shows schematically an oil-well casing l, which is closed at the top, except for a laterally extending nipple 2, to which the well-sounder is attached. There may be another opening, not shown, but generally conventional, through which casing gas is bled on. Within casing I there is ordinarily inserted a tubing 3, made up of pipe sections connected together by collars la-3a. To the bottom of the tubing may be attached a pump, not shown, and within the tubing there may be a string of rods, also not shown, with which the pump is operated. Somewhere within the annular space between casing I and tubing 6 there is found the top of the fluid column 4. The purpose of the apparatus which is here described is to determine the distance from the surface of the ground to the top of the fluid 4.

To nipple 2 in the casing there is attached a valve 6, which is not a part of the well-sounder, but merely serves to close the casing when the well sounder is not in operation. The wellsounder consists of a sound generator-receiver, indicated generally by the numeral 6, connected to nipple 2 through valve 6, and to a conventional electronic amplifier 6 and a conventional recorder 9. The function of the sound generatorreceiver 6 is to produce a sound pulse by the firing of a blank cartridge contained within generator-receiver 6, and also to convert the reflected sound pulses received thereby into electrical impulses which are then fed through wires 1 to amplifier 6, where the electrical impulses are amplified to a level sufllcient to operate recorder 6, which records these pulses on a moving strip of paper 6a in the well known manner. No further description will be given of the amplifier and recorder, since such devices can be built in many different ways well known to those skilled in the art and their details form no part of the present invention.

The construction of sound generator-receiver 6 can best be understood by reference to Figs. 2 and 3. The generator-receiver comprises a vertically disposed strong cylindrical casing l6, closed at the upper end. A recess II is counter-bored in the lower end of casing III to form an annular shoulder l2 against which is mounted a baiile l3, perforated by orifice I4. Below the orifice N there is mounted a small disc i6, which acts as a blast deflector, preventing damage to the fairly delicate sound receiver, which consists essentially of a conical diaphragm ii, to the bottom of which is attached a coil of fine wire II. A permanent magnet l6 and soft iron pole-pieces I6, 26 and 2| produce a radial magnetic fleld through the coil of wire l1, so that any movement of the coil results in the generation or an electrical potential between the ends of this coil. The ends of the coil are connected with flexible wires 2222 which pass through two electrically insulated bushings 26-23, extending through a hollow cap 24, which closes the lower end of easing II, the outer ends of wires 22-22 being connected to leads I going to amplifier I. The structure represented by diaphragm l6, coil II, the magnet and the pole pieces will be recognized as a conventional loud-speaker element, usually employed to convert electrical current into sound, and here employed to convert sound into electrical current.

The loud speaker structure is supported on a ring 26 '(see Figs. 5 and 6 particularly) which is internally shouldered at 26 to receive a peripheral flange 21 of conical diaphragm is and the registering flange of a protective housing 26 enclosing diaphragm I6. These registering flanges are suitably connected to shoulder 26 to form a gas-tight seal therewith. An annular channel 26 is cut in the exterior of ring 26 and a plurality of radially spaced vertical slots ill connect channel 29 with the interior of casing ill above diaphragm l6 and a plurality of radial openlugs 31 through the side wall of ring 26 provide communication between channel 26 and the interior of easing l0 below diaphragm l6. These communicating passageways permit gases to pass from the front to the back of diaphragm l6 and are essential, otherwise the pressure in the well casing when open to the interior of casing l6 during operation of the device would tend to stretch and probably rupture the diaphragm.

Closure of the casing is made gas-tight by means of a rubber ring 22 which is held between the lower end of ring 26 and the face of a laterally extending flange 62 carried by the upper end of cap 24 and slidable inside recess ll of the casing. Flange 33 is urged against rubber ring 22 by means of a threaded ring 34 which engages internal threads 36 provided in the lower end of recess I i.

As shown in Figs. 2 and 3, a pipe nipple 26 communicates with the interior of easing ll. through one side thereof, and serves as a connection for the entire structure to valve 6 in Fig. 1. As best shown in Fig. 3, a tube 31, extends through the opposite side of the casing and into the inner end of pipe-nipple 26; tube 31 being or sufliciently smaller diameter than pipe-nipple 26 to provide an annular space between these two, to thereby provide communication betwc u the well casing and the diaphragm i6. Into the left end of tube 21 there is screwed a cylindrical barrel 26 in which a blank cartridge 66 is fired during the operation of the device.

The firing mechanism is contained within a cylindrical breech block, indicated generally by numeral 46 (Fig. 3), mounted slidably in tube 61 and comprising a pair of end-interlocking tubular members 4| and 42 which are held together by means of a pin 46 extending diametrically through the interlocking end surfaces of members 4| and 42. The outer end of member 42 is provided with a peripheral flange 42:: adapted to engage the outer end of tube 31 to limit the inward movement of breech block 46 into tube 61. The outer end of the bore of member 42 is internally threaded to receive a stud bolt 44 which serves both as a handle for withdrawing and inserting breech block 46 from and into tube II and also as an adjustable thrust member which takes up the recoil when cartridge 29 is fired. A lock nut 46 carried by stud 44 serves to lock stud 44 at the desired position in member 42. The outer ends of sleeve 61 and member 42 are closed by means of a removable housing. indicated generally by the numeral 46, which also encloses stud 44. Housing 46 will be recognized as a conventional pipe union consisting of the usual female member 41 screwed on the outer end of tube 31, a male member 46, the outer end of which is blanked-off to form a closure, and the usual threaded connecting collar nut 46 for completing the union.

Breech-block member 4| is bored out at its outer end to hold slidably a small cylindrical bushing 50, the principal function of which is to hold a light pressure against the cartridge 39; 'a firing pin the end of which is slidable in the bore of bushing 50; and a retractor spring 52, mounted within the bore of member M in compression between the inner end of bushing 50 and the flanged head of the firing pin. In registering slots 53 and 53a cut into adjacent sides of member 4| and tube 31, respectively, there is mounted a lever 54 horizontally pivoted on a pin .55 and bearing against the head of firing pin 5|. Cartridge 39 is held in axial alignment against the end of the breech-block by a retaining ring 58, which has an in-turned lip 51 for engaging the rim of cartridge 39 and is provided with a pair of J-slots 58 by means of which ring 56 is removably attached to the breech-block through conventional engagement with a pair of pins 59 extending from opposite sides of the breech-block.

On the outside of tube 31, but within casing I0, there is welded a vertically disposed lug 60 (Fig. 2). On a pin BI extending downwardly from this lug there is horizontally pivoted a hammer 62, one end of which consists of a vertically extending cylindrical block 63. As shown in Fig. 2, a lug 64 extending from the upper end of block 63 rests on the face of a cam 65 (shown in detail in Fig. 4). A coil spring 66 is connected to the lower end of block 63 and extends therefrom beneath tube 31 to the opposite side of casing I0. Spring 66 is in tension and holds lug 64 against the face of cam-65, except that beyond a trip point 61 on the face of the cam, lug 64 is adapted to slip by under the tension of spring 65 and strike the adjacent edge of lever 54. Cam 65 is rigidly attached by means of a pin 68 to a cylindrical stem 69, which passes out of easing I0 through a conventional stuffing box 10. A handle 1I enables an operator to turn stem 59', and thereby rotate cam 65. Spaced notches 12 and 13 are provided on the face of cam 55 as intermediate safety locks for the hammer.

The operation of the device proceeds as follows: The various elements are connected to the well as shown in Fig. 1. Collar nut 49 of union 46 is loosened, breech block 40 withdrawn from tube 31, cartridge 39 attached to it, as shown in Fig. 3 and described above, and the breech-block with cartridge 39 slipped back into tube 31, the cartridge extending into barrel 38. Tube 31 is then closed with union 46. Valve 5 of Fig. 1 may then be opened, providing communication between the interior of easing I0 and the interior of well casing I. Any gas pressure in the latter will, of course, be transmitted to the interior of easing I0 and such pressure will be equalized therein on opposite sides of diaphragm I6 through the passageways formed by slots 30, channel 29 and openings 3|. At the time the breech block is replaced, cam 65 is rotated so that the lug 64 rests in recess 12 in the cam face. The hammer will thus be partly retracted. Further rotation of the cam in the clockwise direction causes farther retraction of the hammer, until lug 64 slips off trip point 61 of the cam, and strikes lever 54, rotating the latter about pivot pin to thereby propel firing pin 5| into the cap of cartridge 39. The cartridge will explode and the compressional wave created by the explosion will travel down the annular space between well casing I and tubing 2. However, at the instant of the explosion a small portion of the energy will enter the interior of casing Ill through the annular space between tubes 36 and 31 and will traverse orifice I4 and actuate diaphragm I6. The movement of the diaphragm is transformed into an electric current in coil I1. This current is amplified by amplifier 8, and recorded by recorder 9, thus marking the instant of the explosion on the recording tape 9a.

The compressional wave traveling down the space between the casing and the tubing is .partly reflected by any obstructions such as tubing collars 3a, or enlargements, such as the space between the ends of the joints of well casing I, and will ultimately be reflected by the top.

4 of the fluid column. The returning reflected waves all will enter casing I0, traverse orifice I4 and actuate the diaphragm, thus producing a record on chart 9a from which conventional calculations can be made as to the position of the top of the fluid column in the well.

From the foregoing it will be evident that the above-described acoustical well sounder in accordance with this invention comprises a simple, sturdy and compact structure of relatively light weight which lends itself readily to easy handling, ease in disassembly for cleaning and reloading and is highly eflicient in operation.

It will be understood that various alterations and changes may be made in the details of illustrative embodiment above described without departing from the scope of the appended claims but within the spirit of this invention.

What I claim and desire to secure by Letters Patent is:

1. An acoustical well sounding device, comprising, a hollow casing closed at its ends, a partition member extending transversely of said casing intermediate the ends thereof, an axial orifice of restricted area through said partition member, means for establishing communication between the interior of said casing on one side of said partition member and a well to be sounded, sound generating means mounted in said casing on said one side of said partition member, sound receiving means mounted in said casing on the opposite side of said partition member and spaced therefrom, and imperforate baflle means disposed between said orifice and said sound receiving means.

2. An acoustical well sounding device, comprising, a hollow casing closed at its ends,'a partition member extending transversely of said casing intermediate the ends thereof, an axial orifice of restricted area through said partition member providing the sole means for communie cation between the portions of the interior of said casing on opposite sides of said partition member, means for establishing communication between a well to be sounded and the interior of said casing on one side of said partition member. sound generating means mounted in said casing on said one side of said partition member. sound receiving means mounted in said casing on the opposite side of said partition member and spaced therefrom, and an imperforate bafile plate disposed transversely of the axis of said chamber between said orifice and said sound receiving means.

3. An acoustical well sounding device, comprising. a tubular hollow casin closed at one end and having a removable fluid-tight closure for the other end thereof, a tubular connection extending laterally from one side of said casing, a second tubular connection extending through the opposite side of said casing having its inner end extending into the inner end of the first named connection in concentrically spaced relation therewith, a partition member extending transversely across said casing on one side or said connections, an orifice of restricted area through said partition member providing the sole means for communication between the portions of the interior of said casing on opposite sides of said partition member, sound-generatin: means removabLv mounted in said second tubular connection and directed toward said first tubular connection, and sound receiving means mounted in said casing on the side of said partition member opposite said tubular connections and spaced from said partition member, and an imperi'orate baiile plate interposed between said orifice and said sound receiving. means.

ALEXANDER WOLF.

REFERENCES CITED The following references are of record in the die or this patent:

UNITED STATES PATENTS Number Name Date 1,677,943 Williams July 24, 1928 2,232,476 Ritzmann Feb. 18', 1941 2,281,301 Walker Apr. 28, 1942 2,403,535 Kramer July 9, 1946 2,404,784 Bostwick July 30, 1946 2,434,469 Myers Jan. 13, 1948 

